"My family was one of the first to stop using pesticides," says Sattemma, a lively Indian woman in her mid-40s, confidently talking to a group of visiting farmers. "Three years ago, we realised we were spending over half our income on chemicals. It was too much. We were getting into debt and the pesticides were making us ill." Sattemma is in the village of Lakshminayak Thanda in Warangal district of Andhra Pradesh. The visitors are keen to know how she and other villagers are progressing after their decision to stop using pesticides and Bt cotton, the genetically modified variety manufactured by US biotechnology firm Monsanto.

Bt cotton was engineered to combat pests, with the introduction into the cotton seed of a gene from a soil bacterium called Bacillus thuringiensis (Bt), which has a natural insect-killing poison called Bt-toxin. When it was introduced into India at the turn of the century, it was promoted as the "wonder product" that would solve the serious problem of pests, which many of India's 17 million cotton farmers were facing.

Many of the farmers had not been growing cotton as a cash crop for very long. In the late 1980s, under pressure from the International Monetary Fund, India had opened up its strongly protected economy and encouraged its farmers to switch to modern farming, with its hybrid seeds, fertilisers and pesticides. The idea was to turn India into an important exporter of commodities, including cotton.

At first, cotton farmers did well. They got high yields and enjoyed a real increase in income. But then problems arose. The hybrid cotton proved susceptible to pests and diseases, and it was not uncommon for farmers to spray their fields up to 30 times in a single season. Production costs went through the roof and farmers got trapped in debt. They became desperate for a technical fix, and Bt cotton seemed to be the answer.

In its first year of sales, Mahyco-Monsanto sold its entire stock of Bt cotton. According to the company, the area in India under Bt cotton rose from 3.1m acres in 2005 to 14.4m acres in 2007. According to Sekhar Natarajan, regional leader of Monsanto India, Bt cotton yielded 700kg-900kg per acre, compared with 300kg-400kg an acre with conventional seeds.

However, some say that what has been happening on the ground has been very different from the official success story. Scientists Abdul Qayum and Kiran Sakhari assessed Bt cotton's performance in the first three years and found that, despite claims by the company, farmers were not achieving big yields. This perhaps was to be expected, because Bt cotton had been engineered to reduce pesticide use, not to increase yields. But, more surprisingly, they found that pesticide use was not falling either, because farmers were facing serious problems with secondary pests. They worked out that, on average, the income of non-Bt farmers was 60% higher than that of Bt farmers. Monsanto contests these numbers.

There have been other, more alarming problems. In her chat with the visiting farmers, Sattemma says she had seen several of her neighbour's goats die after spending all day grazing on post-harvest Bt cotton plants. Such a story could be dismissed as anecdotal, if it were not backed up by more solid evidence. In 2006, more than 1,800 sheep died in similar circumstances in other villages in Warangal district. The symptoms and post-mortem findings suggested that they had died from severe toxicity. Hundreds of agricultural workers had also developed allergic symptoms when exposed to Bt cotton.

Safety investigation

One might have expected such reports to have led to a thorough investigation into the safety of Bt cotton but, according to the US-based Institute for Responsible Technology, this has never happened. Again, Monsanto contests this account. According to Natarajan, Bt cotton was exhaustively tested for six to eight years before it was authorised for release and there were no reports of adverse impacts on the health of humans or animals.

Less controversial is the financial risk that Bt cotton, along with other hybrids, brings to small farmers. Farmers have traditionally saved seeds from one harvest to another, but this is not possible with hybrids, as they lose vitality. So farmers purchase on credit from middlemen a package of hybrid seed, fertiliser and pesticide, paying back the loan once the crop is harvested. The problems start when a farmer loses a crop through bad weather. Unable to repay, they can easily get caught in a debt trap. Problems were serious before Bt cotton but have got worse because Bt cotton seed is expensive.

Despite these problems, the Indian government believes that cotton has proved a success. In 2006, India overtook the US to become the world's second largest cotton producer (after China). The biotechnology industry is taking the credit, though some farmers are reporting new problems, saying Bt cotton is highly susceptible to wilt. On one occasion a Mahyco-Monsanto representative was taken hostage by irate farmers demanding compensation. More difficulties could lie ahead: a recent study by the Nagpur-based Central Institute for Cotton Research showed that the main cotton pest, bollworms, is becoming resistant to Bt cotton.

Many farmers, like Sattemma, have not followed the debate around Bt cotton. She says it was practical considerations that led to the change in farming. "It was the 15 women in our village's self-help group who got things going," she says. "We were worried about the health of our children. We got the men on our side by showing them that they would save money." Sattemma points to a chart on the wall of a nearby house, on which, with the help of a non-governmental organisation, they have recorded side-by-side the expenses of growing cotton with and without pesticides. Non-pesticide management (NPM), as the system is called, is clearly more profitable, not because yields are higher but because expenditure is so much lower.

In Yenabavi, about 30 miles away, the farmers have gone further, becoming organic and declaring their village GMO-free. Their conversion also began with dissatisfaction with pesticides, this time because they didn't work. "Ten years ago, this field was covered with red-headed hairy caterpillars," says Malliah, the farmer who has led the change. "I kept applying more pesticides but I couldn't get rid of them." By chance, an organic agronomist was visiting. He showed Malliah how to set up solar-powered light traps and, to Malliah's delight, they worked. Since then, he and the other farmers have developed other natural pest controls.

Other villages are following suit. Almost 2,000 in Andhra Pradesh have adopted NPM. Raghuveera Reddy, the state's minister for agriculture wants 2.5m acres under community-managed sustainable agriculture within a few years. The long-term goal is for 10m acres, 45% of the state's cultivable land.

Sustainable agriculture involves hard work and does not guarantee huge profits, but it will not harm the farmers' health, brings personal satisfaction, and involves fewer financial risks. It is crucial to remember what is truly sustainable for small farmers.